Ram air channels are used in vehicles, e.g. aircrafts, for the supply of different systems with ambient air. To name but one example, a ram air channel may be used for supplying an aircraft air-conditioning system with ambient air. In this case, the ambient air may for instance serve for cooling hot bleed air that is used for the pressurization of the aircraft cabin.
Generally, air demand is likely to vary during operation. In order to make it possible to adapt the flow of ambient air supplied through the ram air channel to the varying demand, i.e. different requirements of the systems supplied with the ambient air, there is generally a movable element in the area of an air inlet arrangement and/or in the area of an air outlet arrangement of the ram air channel, or in the ram air channel itself. The movable element allows an increase, a decrease, or even a total closure of the flow cross-section of the air inlet arrangement, the air outlet arrangement or of the ram air channel. US 2009/0253361 A1 and WO 2006/067296 A1, for instance, disclose an arrangement comprising an air passage channel for an aircraft. The cross-section of the air passage channel is adjustable based on the speed and the altitude of the aircraft. To this end, the arrangement comprises a membrane elastically deformable under the action of a fluid control to enable the channel cross-section to be varied.
A steady air flow independent of the current state of a movable element used for regulating the ambient air supply is desirable.